The present invention relates to methods for consolidation treatments in subterranean formations using silicon compounds derived from furfuryl alcohols.
Subterranean wells (e.g., hydrocarbon producing wells or water producing wells) are often stimulated by hydraulic fracturing treatments. In hydraulic fracturing treatments, a viscous treatment fluid is pumped into a portion of a subterranean formation at a rate and pressure such that the subterranean formation breaks down and one or more fractures are formed. While the treatment fluid used to initiate the fracture is generally solids-free, particulate solids, such as graded sand, are typically introduced in a later portion of the treatment fluid and then deposited into the fractures. These particulate solids, or “proppant particulates,” serve to prop the fracture open (e.g., keep the fracture from fully closing) after the hydraulic pressure is removed. By keeping the fracture from fully closing, the proppants aid in forming conductive paths through which produced fluids, such as hydrocarbons, may flow.
Hydraulic fracturing of subterranean wells is often performed in formations that contain unconsolidated particulates. The unconsolidated particulates may migrate out of the subterranean formation and be produced with production fluids. The presence of unconsolidated particulates in a formation during production is undesirable because they may damage or abrade producing equipment and/or reduce well production. For example, unconsolidated particulates may migrate into wellbore casings, perforations, or the interstitial spaces between packed proppants within a fracture and clog or hinder well production. As used herein, the term “unconsolidated particulates” refers to any loose or loosely bonded particulates that move freely with production fluids. Unconsolidated particulates may include, for example, particles and fines naturally found in the formation or particles that have been placed into the formation, such as sand, gravel, fluid loss particles, or drilling particles.
One method of controlling unconsolidated particulates in hydraulic fractured subterranean formations is to perform a gravel-packing treatment. In gravel-packing treatments, particulates are deposited into unconsolidated or weakly consolidated formation zones to create a physical barrier to the transport of unconsolidated particulates with the produced fluids. Typical gravel-packing treatments include placing a screen in a wellbore and packing the annulus between the screen and the wellbore with particulates of a certain size so as to prevent the transport of unconsolidated particulates with the produced fluids without compromising the conductivity of the well. Gravel-packing treatments, however, involve placement of additional unconsolidated particulates into the wellbore that, for example, may not be adequately maintained by a screen and that may, therefore, migrate with the produced fluids, contributing to the problem the gravel-packing treatment was attempting to solve.
Another method of controlling unconsolidated particulates is to resin treat the wellbore. In resin treatments, a resin is placed into the wellbore in order to stabilize unconsolidated particulates. Typically, the resin is used to enhance grain-to-grain or grain-to-formation contact of the unconsolidated particulates such that they are at immobilized or at least resistant to flow pressures of produced fluids. Often, either a silicon-based resin or a furfuryl alcohol-based resin treatment may be utilized. Silicon-based resins are often highly volatile and extremely costly. Moreover, silicon-based resins may provide an unwanted degree of pliability during consolidation treatments such that they fail to adequately consolidate unconsolidated particulates in a subterranean formation. For these reasons, silicon-based resins may not adequately consolidate unconsolidated particulates and may not be preferred due to their extreme expense.
Furfuryl alcohol-based resins may cure independently of a curing agent at extremely high temperatures, typically greater than 270° F. However, many subterranean formations do not reach such temperatures and furfuryl alcohol based resins traditionally require a curing agent at temperatures less than 250° F. However, furfuryl alcohol-based resins are far more cost effective than silicon-based resins, demonstrate chemical ease of use (e.g., handling, application, dilution, robustness, and the like), and are capable of consolidating low permeable formations without substantial interference with production of hydrocarbons, for example. However, furfuryl alcohol-based resins may suffer from brittleness in application. Accordingly, an ongoing need exists for methods of consolidating unconsolidated particulates in a subterranean formation.